题目
计算下面各题。-|||-div dfrac (11)(8)=-|||-dfrac (2)(5)times dfrac (1)(2)=-|||-dfrac (3)(7)+dfrac (5)(14)=-|||-.5-dfrac (1)(6)=-|||-dfrac (15)(32)times dfrac (14)(21)=-|||-div dfrac (2)(9)=-|||-dfrac (1)(24)+dfrac (1)(3)=-|||-times dfrac (3)(4)=-|||-div dfrac (2)(3)=-|||-dfrac (3)(5)times dfrac (2)(3)=-|||-times dfrac (4)(5)=-|||-div dfrac (5)(8)=-|||-dfrac (1)(3)div 4=-|||-dfrac (5)(8)times dfrac (8)(5)=-|||-dfrac (17)(15)times 60=-|||-dfrac (12)(55)times dfrac (29)(36)=-|||-div dfrac (1)(3)=-|||-dfrac (3)(4)times 8=-|||-dfrac (5)(22)times 11=-|||-% div dfrac (1)(8)=-|||-dfrac (1)(3)-dfrac (1)(6)=-|||-dfrac (1)(4)+dfrac (3)(4)=-|||-https:/img.zuoyebang.cc/zyb_33c7127e32233494787be91bf970e419.jpgdiv dfrac (3)(4)=-|||-dfrac (1)(5)times dfrac (1)(9)=-|||-dfrac (4)(5)times dfrac (3)(4)=-|||-dfrac (2)(3)times dfrac (9)(4)=-|||-dfrac (4)(5)times dfrac (1)(4)=-|||-dfrac (3)(7)times dfrac (7)(10)=-|||-.9-dfrac (9)(10)=-|||--dfrac (3)(4)-dfrac (1)(4)=
题目解答
答案
解析
本题主要考查分数的四则运算(加、减、乘、除)以及小数与分数的互化运算,需熟练掌握相关运算法则:
- 分数除法:除以一个分数等于乘以它的倒数,即$a\div\frac{b}{c}=a\times\frac{c}{b}$($a,b,c\neq0$)。
- 分数乘法:分子相乘的积作分子,分母相乘的积作分母,能约分的先约分再计算,即$\frac{a}{b}\times\frac{c}{d}=\frac{ac}{bd}$($b,d\neq0$)。
- 分数加法/减法:先通分(化为同分母分数),再按同分母分数加减法则计算,即$\frac{a}{b}\pm\frac{c}{d}=\frac{ad\pm bc}{bd}$($b,d\neq0$),结果需化为最简分数。
- 小数与分数互化:如$0.5=\frac{1}{2}$,$75\%=\frac{3}{4}$,便于计算。
逐题计算过程:
- $55\div\frac{11}{8}=55\times\frac{8}{11}=5\times8=40$
- $\frac{2}{5}\times\frac{1}{2}=\frac{2\times1}{5\times2}=\frac{1}{5}$(约分:2约掉)
- $\frac{3}{7}+\frac{5}{14}=\frac{6}{14}+\frac{5}{14}=\frac{11}{14}$(通分:7和14的最小公倍数是14)
- $0.5-\frac{1}{6}=\frac{1}{2}-\frac{1}{6}=\frac{3}{6}-\frac{1}{6}=\frac{2}{6}=\frac{1}{3}$(通分:2和6的最小公倍数是6,化简)
- $\frac{15}{32}\times\frac{14}{21}=\frac{15\times14}{32\times21}=\frac{15\times2}{32\times3}=\frac{30}{96}=\frac{5}{16}$(约分:14和21约7,15和3约3)
- $100\div\frac{2}{9}=100\times\frac{9}{2}=50\times9=450$
- $\frac{1}{24}+\frac{1}{3}=\frac{1}{24}+\frac{8}{24}=\frac{9}{24}=\frac{3}{8}$(通分:24和3的最小公倍数是24,化简)
- $4\times\frac{3}{4}=3$(4和4约掉)
- $12\div\frac{2}{3}=12\times\frac{3}{2}=6\times3=18$(原题答案此处可能笔误,应为18)
- $\frac{3}{5}\times\frac{2}{3}=\frac{3\times2}{5\times3}=\frac{2}{5}$(3约掉)
- $25\times\frac{4}{5}=5\times4=20$(25和5约5)
- $10\div\frac{5}{8}=10\times\frac{8}{5}=2\times8=16$
- $\frac{1}{3}\div4=\frac{1}{3}\times\frac{1}{4}=\frac{1}{12}$
- $\frac{5}{8}\times\frac{8}{5}=1$(分子分母交叉约掉)
- $\frac{17}{15}\times60=17\times4=68$(60和15约15)
- $\frac{12}{55}\times\frac{29}{36}=\frac{12\times29}{55\times36}=\frac{29}{55\times3}=\frac{29}{165}$(12和36约12)
- $12\div\frac{1}{3}=12\times3=36$
- $\frac{3}{4}\times8=3\times2=6$(8和4约4)
- $\frac{5}{22}\times11=\frac{5}{2}$(11和22约11)
- $75\%\div\frac{1}{8}=\frac{3}{4}\times8=6$(75%=$\frac{3}{4}$)
- $\frac{1}{3}-\frac{1}{6}=\frac{2}{6}-\frac{1}{6}=\frac{1}{6}$(通分:3和6的最小公倍数是6)
- $\frac{1}{4}+\frac{3}{4}=1$(同分母相加,分子1+3=4,4/4=1)
- $1\div\frac{3}{4}=1\times\frac{4}{3}=\frac{4}{3}$
- $\frac{1}{5}\times\frac{1}{9}=\frac{1}{45}$(分子分母直接相乘)
- $\frac{4}{5}\times\frac{3}{4}=\frac{3}{5}$(4约掉)
- $\frac{2}{3}\times\frac{9}{4}=\frac{2\times9}{3\times4}=\frac{18}{12}=\frac{3}{2}$(约分:2和4约2,9和3约3)
- $\frac{4}{5}\times\frac{1}{4}=\frac{1}{5}$(4约掉)
- $\frac{3}{7}\times\frac{7}{10}=\frac{3}{10}$(7约掉)
- $0.9-\frac{9}{10}=\frac{9}{10}-\frac{9}{10}=0$(0.9=$\frac{9}{10}$)
- $10-\frac{3}{4}-\frac{1}{4}=10-(\frac{3}{4}+\frac{1}{4})=10-1=9$(加法结合律,$\frac{3}{4}+\frac{1}{4}=1$)